508 Scientific Proceedings, Royal Dublin Society. 



by its antitlieton the onto-motiou. It is well, therefore, to use the 

 prefixes onto- and syntheto- (or the equivalent adjectives antic and 

 objective) when there is any risk of mistake. 1 



It is in accordance with the signification we have hitherto given 

 to the word real that motion in the phenomenal world shall be 

 deemed real when it is a syntheton of the actual perceptions which 

 an onto-motion does, and of the potential perceptions which it could 

 produce by acting on human minds through human senses. But 

 Science, in its progress, has found this definition too cramped. 

 The definition would limit the stamp of being real to those cases 

 in which man's senses are competent to act as channels of commu- 

 nication between the sense-compelling universe and him. Now, 

 scientific investigation has penetrated much further than this — 

 even the flimsy appreciation of what goes on in Nature, which is 

 necessary for man's every-day work, renders essential some ex- 

 tension of the meaning of the word real — and accordingly the 

 exigencies of common life, but more especially of scientific inquiry, 

 have made a very marked extension inevitable, so that a motion or 

 other part of the Phenomenal Hypotheton is still to be regarded 

 as real, although too small, or in some other way unfitted, to be a 

 syntheton of human perceptions, whenever justification for this 

 extension exists. It would, however, draw us too much aside from 

 the main topic of this essay to deal adequately on the present oc- 

 casion with this most interesting extension, so that I must content 

 myself here with a bare reference to it. The phenomenal object 

 of the scientific student of Nature is accordingly a syntheton of — 



1°. Actual perceptions, 



2°. Potential perceptions, and of 



3°. Certain conceived perceptions, viz. those others beside 

 actual and potential, which scientific investigation does or can 

 warrant. 



1 In the text the word motion is used in the two possible senses pointed out in the 

 foot-note on p. 490, and these two meanings of the word are distinguished as the onto- 

 motion and the syntheto-motion. It will usually be found more convenient to confine 

 the meaning of the word motion to the latter sense, i. e. to use it only for phenomenal, 

 objective, or syntheto-motion. The other meaning may then be indicated by the word 

 anti-motion, which will then mean the same as the antitheton of this phenomenal 

 motion. The two events will then be distinguished as motion, the apparent event in 

 the phenomenal world, and anti-motion, that which has actually occurred in the autic 

 universe. 



